Adjustments to Disposal

- Seal the Client classes (no finalizers here)
- Make dispose/async virtual instead of explicit so it will be called in the standard way
- When disposing EventStoreClient cancel the cts
- When disposing EventStoreClient don't create a batchappender if there wasn't one.

src/EventStore.Client.Operations/EventStoreOperationsClient.cs

@@ -11,7 +11,7 @@ namespace EventStore.Client {
 	/// <summary>
 	/// The client used to perform maintenance and other administrative tasks on the EventStoreDB.
 	/// </summary>
-	public partial class EventStoreOperationsClient : EventStoreClientBase {
+	public sealed partial class EventStoreOperationsClient : EventStoreClientBase {
 		private static readonly IDictionary<string, Func<RpcException, Exception>> ExceptionMap =
 			new Dictionary<string, Func<RpcException, Exception>> {
 				[Constants.Exceptions.ScavengeNotFound] = ex => new ScavengeNotFoundException(ex.Trailers

src/EventStore.Client.PersistentSubscriptions/EventStorePersistentSubscriptionsClient.cs

@@ -10,7 +10,7 @@ namespace EventStore.Client {
 	/// <summary>
 	/// The client used to manage persistent subscriptions in the EventStoreDB.
 	/// </summary>
-	public partial class EventStorePersistentSubscriptionsClient : EventStoreClientBase {
+	public sealed partial class EventStorePersistentSubscriptionsClient : EventStoreClientBase {
 		private readonly ILogger _log;
 
 		/// <summary>

src/EventStore.Client.ProjectionManagement/EventStoreProjectionManagementClient.cs

@@ -10,7 +10,7 @@ namespace EventStore.Client {
 	/// <summary>
 	///The client used to manage projections on the EventStoreDB.
 	/// </summary>
-	public partial class EventStoreProjectionManagementClient : EventStoreClientBase {
+	public sealed partial class EventStoreProjectionManagementClient : EventStoreClientBase {
 		private readonly ILogger _log;
 
 		/// <summary>

src/EventStore.Client.Streams/EventStoreClient.cs

@@ -18,12 +18,7 @@ namespace EventStore.Client {
 	/// <summary>
 	/// The client used for operations on streams.
 	/// </summary>
-	public partial class EventStoreClient : EventStoreClientBase,
-// todo: remove these long with the explicit implementations
-#if !GRPC_CORE
-		IDisposable,
-#endif
-		IAsyncDisposable {
+	public sealed partial class EventStoreClient : EventStoreClientBase {
 
 		private static readonly JsonSerializerOptions StreamMetadataJsonSerializerOptions = new() {
 			Converters = {
@@ -35,9 +30,9 @@ public partial class EventStoreClient : EventStoreClientBase,
 #if NET5_0_OR_GREATER
 		private Lazy<StreamAppender> _streamAppenderLazy;
 		private StreamAppender _streamAppender => _streamAppenderLazy.Value;
+		private readonly CancellationTokenSource _disposedTokenSource;
 #endif
 
-		private readonly CancellationTokenSource _disposedTokenSource;
 
 		private static readonly Dictionary<string, Func<RpcException, Exception>> ExceptionMap = new() {
 			[Constants.Exceptions.InvalidTransaction] =
@@ -76,8 +71,8 @@ public EventStoreClient(IOptions<EventStoreClientSettings> options) : this(optio
 		/// <param name="settings"></param>
 		public EventStoreClient(EventStoreClientSettings? settings = null) : base(settings, ExceptionMap) {
 			_log = Settings.LoggerFactory?.CreateLogger<EventStoreClient>() ?? new NullLogger<EventStoreClient>();
-			_disposedTokenSource = new CancellationTokenSource();
 #if NET5_0_OR_GREATER
+			_disposedTokenSource = new CancellationTokenSource();
 			_streamAppenderLazy = new Lazy<StreamAppender>(CreateStreamAppender);
 #endif
 		}
@@ -166,22 +161,26 @@ private StreamAppender CreateStreamAppender() {
 			return options;
 		}
 
-#if !GRPC_CORE
-		void IDisposable.Dispose() {
-#if NET5_0_OR_GREATER
-			_streamAppender.Dispose();
-#endif
+#if !GRPC_CORE && NET5_0_OR_GREATER
+		/// <inheritdoc />
+		public override void Dispose() {
+			_disposedTokenSource.Cancel();
+			if (_streamAppenderLazy.IsValueCreated)
+				_streamAppenderLazy.Value.Dispose();
 			_disposedTokenSource.Dispose();
 			base.Dispose();
 		}
 #endif
 
-		async ValueTask IAsyncDisposable.DisposeAsync() {
 #if NET5_0_OR_GREATER
-			_streamAppender.Dispose();
-#endif
+		/// <inheritdoc />
+		public override async ValueTask DisposeAsync() {
+			_disposedTokenSource.Cancel();
 			_disposedTokenSource.Dispose();
+			if (_streamAppenderLazy.IsValueCreated)
+				_streamAppenderLazy.Value.Dispose();
 			await base.DisposeAsync().ConfigureAwait(false);
 		}
+#endif
 	}
 }

src/EventStore.Client.UserManagement/EventStoreUserManagementClient.cs

@@ -14,7 +14,7 @@ namespace EventStore.Client {
 	/// <summary>
 	/// The client used for operations on internal users.
 	/// </summary>
-	public class EventStoreUserManagementClient : EventStoreClientBase {
+	public sealed class EventStoreUserManagementClient : EventStoreClientBase {
 		private readonly ILogger _log;
 
 		/// <summary>

src/EventStore.Client/EventStoreClientBase.cs

@@ -98,15 +98,15 @@ private void Rediscover() {
 
 #if !GRPC_CORE
 		/// <inheritdoc />
-		public void Dispose() {
+		public virtual void Dispose() {
 			_cts.Cancel();
 			_cts.Dispose();
 			_channelCache.Dispose();
 		}
 #endif
 
 		/// <inheritdoc />
-		public async ValueTask DisposeAsync() {
+		public virtual async ValueTask DisposeAsync() {
 			_cts.Cancel();
 			_cts.Dispose();
 			await _channelCache.DisposeAsync().ConfigureAwait(false);